feat: add interactive mode to coco ask

[linw1995]

Implements -i/--interactive flag for coco ask (Issue #169), enabling user approval before tool execution.

Changes

• Add -i flag to coco ask for interactive approval workflow
• Extend session socket protocol for prompt/reply flow
• Route tool permissions through TUI for confirmation
• Add E2E test infrastructure with mock OpenAI server

Behavior

• Interactive combos wait for user feedback before reply
• Bash tool confirmations route through combo context
• Cancelled tools allow continued feedback (combo stays alive)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 15.16484% with 1930 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.95%. Comparing base (c3970cb) to head (e8744ab).
⚠️ Report is 13 commits behind head on dev.

Files with missing lines	Patch %	Lines
crates/coco-tui/src/e2e_tests/support.rs	0.00%	721 Missing ⚠️
src/combo/runner.rs	26.66%	407 Missing ⚠️
crates/coco-tui/src/e2e_tests/combo_interactive.rs	0.00%	387 Missing ⚠️
crates/coco-tui/src/components/chat.rs	0.00%	336 Missing ⚠️
crates/coco-tui/src/e2e_tests/startup.rs	0.00%	38 Missing ⚠️
crates/coco-tui/src/components/messages/combo.rs	26.66%	22 Missing ⚠️
src/main.rs	0.00%	8 Missing ⚠️
src/tools/bash.rs	92.10%	6 Missing ⚠️
src/combo/starter.rs	91.11%	4 Missing ⚠️
src/agent/executor.rs	95.65%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #176      +/-   ##
==========================================
- Coverage   47.59%   45.95%   -1.65%     
==========================================
  Files         100      108       +8     
  Lines       27316    30091    +2775     
==========================================
+ Hits        13000    13827     +827     
- Misses      14316    16264    +1948     

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