refactor: split input and UI by feature

[zatevakhin]

What changed

• Split Chat, Sessions/Delegates, popup features, and Navigation/Diagnostics views into feature-owned modules.
• Added typed, data-only feature-owned input result boundaries.
• Kept effects, commands, persistence, connectivity, popup/screen routing, slash commands, broad chords, and cross-feature coordination at the root.
• Preserved the nine-stage router precedence and behavior-sensitive prompt, session, delegate, model, theme, and clipboard ordering.

Reviewed range

Base a1c6a096f5d244aa39d10c990660ab3f27429d7a through head 976115eaa83c39e0cd2556d36268040a3b41c018 (13 contiguous commits, 65 paths, +13,525/-8,106):

1. test: characterize input and view dispatch boundaries
2. refactor: split chat card and tool views
3. refactor: split chat editor views
4. refactor: split chat screen views
5. refactor: split session and delegate views
6. refactor: split feature popup views
7. refactor: split navigation popup views
8. refactor: extract elicitation input
9. refactor: extract composer input
10. refactor: extract chat input coordination
11. refactor: extract session and delegate input
12. refactor: extract popup feature input
13. refactor: extract navigation and diagnostics input

Every implementation slice and the aggregate range were independently reviewed and approved with no findings; the aggregate architecture audit also passed.

Validation

All final gates passed on exact head 976115eaa83c39e0cd2556d36268040a3b41c018:

• cargo fmt --all -- --check
• cargo check --all-targets --all-features
• cargo clippy --all-targets --all-features -- -D warnings
• cargo build --all-targets --all-features
• cargo test --all-targets --all-features: 1170 passed, 0 failed
• cargo test --release --all-targets --all-features: 1170 passed, 0 failed
• cargo test --all-targets: 1170 passed, 0 failed
• cargo test --release --all-targets: 1170 passed, 0 failed
• Aggregate git diff --check, protected-path audit, structural dependency searches, and final tracked-tree cleanliness checks passed.

No live ACP/terminal UI smoke environment was available. Automated debug/release coverage is green, but live backend and interactive terminal behavior remain a residual environmental validation risk.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 197f564e-dd5d-4067-99f7-f6b59947ba4c

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

_{Comment @coderabbitai help to get the list of available commands.}