feat(imports): generate executables from python scripts

[jahvon]

Part 5/5. Stacked on #442.

Summary

Adds .py to the script types imports: can turn into executables, so a repo's Python scripts become named, discoverable flow executables alongside its shell ones.

imports:
  - "scripts/analyze.py"

#!/usr/bin/env python3
# f:name=metrics f:verb=analyze
# f:description="Analyze project metrics"
# f:tag=reporting

→ flow analyze metrics

Notable Changes

• Python uses # line comments, so the existing f:name= / f:verb= metadata syntax and its parser work unchanged — the new parser is the shell one with a different extension.
• The generated executable leaves interpreter unset: the .py extension already routes it (Part 1), and setting the field would add noise to every generated definition.
• Docs updated in both executables.md (import table + a Python tab in the metadata examples) and generated-config.md (supported types, comment-prefix note, and Python tabs in the params/args examples).

Testing

• Parser tests mirroring the ps1 set (simple / complex / params), plus two cases the others do not have: metadata following a shebang line — idiomatic in Python scripts, and it must not shadow the comments beneath it — and that the generated executable leaves interpreter unset while still resolving to Python via its extension.
• An import-dispatch test alongside the existing .sh/.bat/.ps1 ones.
• Verified end-to-end outside the test suite: a scratch workspace importing a .py, synced, then run — metadata, tags, and description all landed, and flow analyze metrics executed it under Python.
• flow validate passes; generate produces no diff.

🤖 Generated with Claude Code

https://claude.ai/code/session_01R328pa3FUUfga4gYah1iQi

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/fileparser/py_file_parser.go	81.81%	2 Missing and 2 partials ⚠️

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