docs: rewrite project documentation for v2 architecture

Rewrite all documentation to reflect the new five-layer architecture,
updated CLI surface, and current development workflows.

- AGENTS.md: restructure for machine-first readability with decision
  trees, anti-patterns, and layer invariants
- README.md: rewrite for current CLI commands and agent optimization
- docs/architecture.md: document five-layer component organization
- docs/development.md: add service/resolver/command templates
- docs/testing.md: add mock patterns per layer
- docs/build-system.md: document codegen pipeline
- docs/files.md: update file catalog for new structure

Remove obsolete files:
- docs/Linear-API@current.graphql (26k-line schema dump)
- docs/plans/ (completed implementation plans)

Part of #45
Refs #54

Author: iamfj

.github/FUNDING.yml

@@ -1,15 +1 @@
-# These are supported funding model platforms
-
-github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
-patreon: # Replace with a single Patreon username
-open_collective: # Replace with a single Open Collective username
-ko_fi: # Replace with a single Ko-fi username
-tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
-community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
-liberapay: # Replace with a single Liberapay username
-issuehunt: # Replace with a single IssueHunt username
-lfx_crowdfunding: # Replace with a single LFX Crowdfunding project-name e.g., cloud-foundry
-polar: # Replace with a single Polar username
-buy_me_a_coffee: # Replace with a single Buy Me a Coffee username
-thanks_dev: # Replace with a single thanks.dev username
-custom: ["https://actions.work/store/#sponsoring"] # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
+custom: ["https://actions.work/store/#sponsoring"]