fix: pdd-change Step 6 should use <pdd-dependency> tags, not <include> tags

[agarwal-ishaan]

Summary

pdd change Step 6 built its module-dependency context by scanning <include> tags (build_dependency_graph()), but <include> tags are LLM context, not declared architectural dependencies. A module can truly depend on another via <pdd-dependency> without ever <include>-ing it, and can <include> another module's example purely for style without depending on it at all -- so the old graph both missed real dependents and fabricated false ones.

1. Prompts (pdd/prompts/sync_order_python.prompt, pdd/prompts/agentic_change_orchestrator_python.prompt): specify a new build_dependency_graph_from_architecture() function and wire Step 6's dependency context to use it.
2. pdd/sync_order.py: implements build_dependency_graph_from_architecture(architecture_path) -> Dict[str, List[str]], reading architecture.json's dependencies field (populated from <pdd-dependency> tags by architecture_sync.py) instead of scanning <include> tags. Generated via pdd generate --incremental.
3. pdd/agentic_change_orchestrator.py: _build_dependency_context() now takes architecture_path and calls the function above instead of the include-based build_dependency_graph(prompts_dir) -- the actual Step 6 behavior fix.

Test plan

• pytest tests/test_sync_order.py -- 52 passed
• pytest tests/test_agentic_change_orchestrator.py -- 265 passed
• Manual repro (pdd-issue-1807-repro/): _build_dependency_context() now correctly shows payment_status -> affects: customer_service (previously missing) and no longer fabricates legacy_wizard -> affects: onboarding
• Confirmed no regression: sibling modules (agentic_sync, sync_graph_order_consistency) that also import from sync_order still import cleanly

Fixes #1807

[gltanaka]

/heal

[gltanaka]

Thanks for consolidating the earlier prompt and implementation PRs. The architecture-based direction is sensible, but this version has two merge-blocking correctness problems:

1. architecture.json.dependencies is not currently a <pdd-dependency>-only data source. merge_auto_deps_includes_into_architecture() intentionally writes module/example <include> targets into the same array, and existing tests require that behavior. Consequently, reading this field cannot prove that an include-only module edge is excluded. The new Step 6 test hand-writes JSON without the include edge, so it does not exercise the real prompt → architecture → Step 6 path.

2. build_dependency_graph_from_architecture() uses extract_module_from_include() for architecture identities. That helper drops directories and rejects _LLM.prompt files. This loses real declared dependencies in the current repository. For example, commands/gate_python.prompt -> gate_python.prompt collapses to gate -> gate and is discarded as a self-edge; dependencies such as agentic_update_python.prompt -> agentic_update_LLM.prompt are also omitted.

Please resolve the dependency provenance/semantics and use a path-preserving architecture identity that supports LLM modules. Add regressions for:

• a real prompt-to-architecture-to-Step-6 flow distinguishing <pdd-dependency> from context-only <include>;
• path-qualified modules with the same basename;
• _LLM.prompt dependencies;
• root plus nested architecture files.

The focused suites pass (317 tests), but they cover only flat _python.prompt names and do not exercise these production shapes. Follow-up scope should also address the issue's requested prompting-guide examples and the retained top-30/top-10 truncation.

[agarwal-ishaan]

Implemented the above changes, requesting you to please review