ML-187: restructure pre-commit checks to run conditionally

Gate each check behind staged file pattern matching so a docs
or backlog change no longer triggers the full test suite. Add
presto pytest and Docker image validation guards. Fall back to
running all checks when invoked directly (not via git commit).

AGENTS.md

@@ -29,13 +29,15 @@ Before exploring the codebase for any task, read `docs/architecture.md`. Do this
 
 <!-- usage-rules-start -->
 <!-- usage_rules-start -->
+
 ## usage_rules usage
+
 _A config-driven dev tool for Elixir projects to manage AGENTS.md files and agent skills from dependencies_
 
 ## Using Usage Rules
 
-Many packages have usage rules, which you should *thoroughly* consult before taking any
-action. These usage rules contain guidelines and rules *directly from the package authors*.
+Many packages have usage rules, which you should _thoroughly_ consult before taking any
+action. These usage rules contain guidelines and rules _directly from the package authors_.
 They are your best source of knowledge for making decisions.
 
 ## Modules & functions in the current app and dependencies
@@ -54,10 +56,9 @@ mix usage_rules.docs Enum.zip
 mix usage_rules.docs Enum.zip/1
 ```
 
-
 ## Searching Documentation
 
-You should also consult the documentation of any tools you are using, early and often. The best 
+You should also consult the documentation of any tools you are using, early and often. The best
 way to accomplish this is to use the `usage_rules.search_docs` mix task. Once you have
 found what you are looking for, use the links in the search results to get more detail. For example:
 
@@ -75,23 +76,27 @@ mix usage_rules.search_docs "making requests" -p req
 mix usage_rules.search_docs "Enum.zip" --query-by title
 ```
 
-
 <!-- usage_rules-end -->
 <!-- usage_rules:elixir-start -->
+
 ## usage_rules:elixir usage
+
 # Elixir Core Usage Rules
 
 ## Pattern Matching
+
 - Use pattern matching over conditional logic when possible
 - Prefer to match on function heads instead of using `if`/`else` or `case` in function bodies
 - `%{}` matches ANY map, not just empty maps. Use `map_size(map) == 0` guard to check for truly empty maps
 
 ## Error Handling
+
 - Use `{:ok, result}` and `{:error, reason}` tuples for operations that can fail
 - Avoid raising exceptions for control flow
 - Use `with` for chaining operations that return `{:ok, _}` or `{:error, _}`
 
 ## Common Mistakes to Avoid
+
 - Elixir has no `return` statement, nor early returns. The last expression in a block is always returned.
 - Don't use `Enum` functions on large collections when `Stream` is more appropriate
 - Avoid nested `case` statements - refactor to a single `case`, `with` or separate functions
@@ -104,6 +109,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 - There are many useful standard library functions, prefer to use them where possible
 
 ## Function Design
+
 - Use guard clauses: `when is_binary(name) and byte_size(name) > 0`
 - Prefer multiple function clauses over complex conditional logic
 - Name functions descriptively: `calculate_total_price/2` not `calc/2`
@@ -111,6 +117,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 - Names like `is_thing` should be reserved for guards
 
 ## Data Structures
+
 - Use structs over maps when the shape is known: `defstruct [:name, :age]`
 - Prefer keyword lists for options: `[timeout: 5000, retries: 3]`
 - Use maps for dynamic key-value data
@@ -123,6 +130,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 - Read the docs and options fully before using tasks
 
 ## Testing
+
 - Run tests in a specific file with `mix test test/my_test.exs` and a specific test with the line number `mix test path/to/test.exs:123`
 - Limit the number of failed tests with `mix test --max-failures n`
 - Use `@tag` to tag specific tests, and `mix test --only tag` to run only those tests
@@ -135,26 +143,32 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 
 <!-- usage_rules:elixir-end -->
 <!-- usage_rules:otp-start -->
+
 ## usage_rules:otp usage
+
 # OTP Usage Rules
 
 ## GenServer Best Practices
+
 - Keep state simple and serializable
 - Handle all expected messages explicitly
 - Use `handle_continue/2` for post-init work
 - Implement proper cleanup in `terminate/2` when necessary
 
 ## Process Communication
+
 - Use `GenServer.call/3` for synchronous requests expecting replies
 - Use `GenServer.cast/2` for fire-and-forget messages.
 - When in doubt, use `call` over `cast`, to ensure back-pressure
 - Set appropriate timeouts for `call/3` operations
 
 ## Fault Tolerance
+
 - Set up processes such that they can handle crashing and being restarted by supervisors
 - Use `:max_restarts` and `:max_seconds` to prevent restart loops
 
 ## Task and Async
+
 - Use `Task.Supervisor` for better fault tolerance
 - Handle task failures with `Task.yield/2` or `Task.shutdown/2`
 - Set appropriate task timeouts
@@ -162,13 +176,15 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 
 <!-- usage_rules:otp-end -->
 <!-- usage_rules-start -->
+
 ## usage_rules usage
+
 _A config-driven dev tool for Elixir projects to manage AGENTS.md files and agent skills from dependencies_
 
 ## Using Usage Rules
 
-Many packages have usage rules, which you should *thoroughly* consult before taking any
-action. These usage rules contain guidelines and rules *directly from the package authors*.
+Many packages have usage rules, which you should _thoroughly_ consult before taking any
+action. These usage rules contain guidelines and rules _directly from the package authors_.
 They are your best source of knowledge for making decisions.
 
 ## Modules & functions in the current app and dependencies
@@ -187,10 +203,9 @@ mix usage_rules.docs Enum.zip
 mix usage_rules.docs Enum.zip/1
 ```
 
-
 ## Searching Documentation
 
-You should also consult the documentation of any tools you are using, early and often. The best 
+You should also consult the documentation of any tools you are using, early and often. The best
 way to accomplish this is to use the `usage_rules.search_docs` mix task. Once you have
 found what you are looking for, use the links in the search results to get more detail. For example:
 
@@ -208,23 +223,27 @@ mix usage_rules.search_docs "making requests" -p req
 mix usage_rules.search_docs "Enum.zip" --query-by title
 ```
 
-
 <!-- usage_rules-end -->
 <!-- usage_rules:elixir-start -->
+
 ## usage_rules:elixir usage
+
 # Elixir Core Usage Rules
 
 ## Pattern Matching
+
 - Use pattern matching over conditional logic when possible
 - Prefer to match on function heads instead of using `if`/`else` or `case` in function bodies
 - `%{}` matches ANY map, not just empty maps. Use `map_size(map) == 0` guard to check for truly empty maps
 
 ## Error Handling
+
 - Use `{:ok, result}` and `{:error, reason}` tuples for operations that can fail
 - Avoid raising exceptions for control flow
 - Use `with` for chaining operations that return `{:ok, _}` or `{:error, _}`
 
 ## Common Mistakes to Avoid
+
 - Elixir has no `return` statement, nor early returns. The last expression in a block is always returned.
 - Don't use `Enum` functions on large collections when `Stream` is more appropriate
 - Avoid nested `case` statements - refactor to a single `case`, `with` or separate functions
@@ -237,6 +256,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 - There are many useful standard library functions, prefer to use them where possible
 
 ## Function Design
+
 - Use guard clauses: `when is_binary(name) and byte_size(name) > 0`
 - Prefer multiple function clauses over complex conditional logic
 - Name functions descriptively: `calculate_total_price/2` not `calc/2`
@@ -244,6 +264,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 - Names like `is_thing` should be reserved for guards
 
 ## Data Structures
+
 - Use structs over maps when the shape is known: `defstruct [:name, :age]`
 - Prefer keyword lists for options: `[timeout: 5000, retries: 3]`
 - Use maps for dynamic key-value data
@@ -256,6 +277,7 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 - Read the docs and options fully before using tasks
 
 ## Testing
+
 - Run tests in a specific file with `mix test test/my_test.exs` and a specific test with the line number `mix test path/to/test.exs:123`
 - Limit the number of failed tests with `mix test --max-failures n`
 - Use `@tag` to tag specific tests, and `mix test --only tag` to run only those tests
@@ -268,10 +290,13 @@ mix usage_rules.search_docs "Enum.zip" --query-by title
 
 <!-- usage_rules:elixir-end -->
 <!-- mdex-start -->
+
 ## mdex usage
+
 _Fast and extensible Markdown for Elixir_
 
 @deps/mdex/usage-rules.md
+
 <!-- mdex-end -->
 <!-- usage-rules-end -->
 
@@ -293,6 +318,7 @@ This project uses Backlog.md MCP for all task and project management activities.
 - **When to read it**: BEFORE creating tasks, or when you're unsure whether to track work
 
 These guides cover:
+
 - Decision framework for when to create tasks
 - Search-first workflow to avoid duplicates
 - Links to detailed guides for task creation, execution, and finalization