docs(#1605): document dual-model architecture

[fullsend-ai-coder]

Add a "Dual-Model Architecture" subsection to AGENTS.md under Architecture, after the Adapter Pattern section. The new section explains that the service maintains two parallel resource flows (ComponentGroup and Application) and that cross-cutting features must cover both flows until the Application model is fully deprecated. It references key dual-path files and the TODO comment pattern used to mark Application-model code paths.

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Closes #1605

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[fullsend-ai-review]

🤖 Finished Review · ✅ Success · Started 9:23 PM UTC · Completed 9:32 PM UTC
Commit: ec21706 · View workflow run →

[fullsend-ai-review]

Review

Findings

Medium

• [protected-path] AGENTS.md — This file is under a protected path (AGENTS.md) and requires human approval regardless of automated review outcome. The PR links to issue Document dual-model (Application + ComponentGroup) completeness requirement in AGENTS.md #1605 and explains the rationale for the change (documenting dual-model architecture to help automated reviewers catch completeness bugs). Human reviewers should verify the documentation addition is accurate and appropriate.

Low

• [technical accuracy] AGENTS.md:46 — The documentation says to look for TODO: remove when we deprecate old application model comments, but the actual TODO comments in the codebase use many different phrasings (at least 12 variants across 50+ occurrences). Only ~1 instance exactly matches the documented string. A developer relying on this exact string would miss the vast majority of Application-model code paths.
  Remediation: Use a broader description such as: "Look for TODO comments referencing deprecation of the application model (search for TODO.*application case-insensitively) to identify Application-model code paths."

• [Structure and organization] AGENTS.md:40 — The new "Dual-Model Architecture" subsection is inserted between "Adapter Pattern" and "Resource Loading", interrupting the logical flow between these two foundational pattern descriptions. Consider placing it after "Resource Loading" or within "Additional Key Patterns".

• [Formatting consistency] AGENTS.md:42 — The new paragraph is denser than existing Architecture subsections (which use 1-2 concise sentences). The single paragraph packs multiple parenthetical code examples and em-dash clauses. Consider breaking into 2-3 shorter sentences to match the established terse style.

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Labels: PR modifies documentation (AGENTS.md)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.78%. Comparing base (554730a) to head (66fbb28).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1606      +/-   ##
==========================================
+ Coverage   73.58%   73.78%   +0.20%     
==========================================
  Files          70       70              
  Lines        9377     9377              
==========================================
+ Hits         6900     6919      +19     
+ Misses       1777     1762      -15     
+ Partials      700      696       -4     

Flag	Coverage Δ
e2e-tests	45.01% <ø> (+0.31%)	⬆️
unit-tests	66.73% <ø> (-0.12%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.
see 9 files with indirect coverage changes

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