Extract agent and tools from tracker mapping worker into dedicated files

Split tracker_mapping_worker.go: agent construction, prompts, and
structured output type move to tracker_mapping_agent.go; each tool gets
its own *_tool.go file. Update naming conventions (worker, agent, tool
file patterns, AgentResult suffix, RunTyped preference).

Signed-off-by: Émile Ré <emile@probo.com>

contrib/claude/agent.md

@@ -24,7 +24,17 @@ result.FinalMessage().Text()  // final output
 result.LastAgent              // agent that produced the result
 ```
 
-Typed output via `RunTyped[T](ctx, agent, messages)` — validates against JSON Schema.
+Prefer `RunTyped[T]` over `Run` + manual unmarshalling when the agent declares a
+structured output type via `WithOutputType`. `RunTyped` validates the response
+against the JSON Schema and returns the typed value directly:
+
+```go
+result, err := agent.RunTyped[TrackerIdentification](ctx, ag, messages)
+identification := result.Output  // already typed, no json.Unmarshal needed
+```
+
+Only fall back to `agent.Run` when the agent produces free-form text with no
+output schema.
 
 ## Tool interface
 

contrib/claude/file-naming.md

@@ -27,3 +27,40 @@ Use one of: {{.Categories}}.
 
 For single-placeholder templates, `strings.Replace` is sufficient. For multiple
 placeholders, use `text/template`.
+
+## Worker files
+
+Background worker files use the `<name>_worker.go` naming pattern. The file
+contains the handler struct, `NewXxxWorker` constructor, and the `Claim`/`Process`
+methods. Keep domain-specific helper methods (match, resolve, etc.) in the same
+file.
+
+```
+pkg/cookiebanner/tracker_mapping_worker.go
+pkg/cookiebanner/pattern_analysis_worker.go
+```
+
+## Agent files
+
+When a package has a worker that uses an agent, the agent construction logic
+goes in `<worker_prefix>_agent.go` alongside `<worker_prefix>_worker.go`. The
+worker file stays focused on `Claim`/`Process` and handler methods; the agent
+file owns agent construction, prompt building, constants, config, and the
+`//go:embed` directive for prompt templates.
+
+```
+pkg/cookiebanner/tracker_mapping_worker.go   -- worker handler
+pkg/cookiebanner/tracker_mapping_agent.go    -- agent construction + prompts
+```
+
+## Tool files
+
+Each agent tool lives in its own `<tool_name>_tool.go` file, named after the
+tool constructor function (without the `Tool` suffix). The file contains the
+constructor function plus its param/result types. Avoid grouping multiple tools
+in a single file.
+
+```
+pkg/cookiebanner/search_tracker_patterns_tool.go   -- searchTrackerPatternsTool
+pkg/cookiebanner/search_third_parties_tool.go       -- searchThirdPartiesTool
+```