feat(tui): add session delete confirmation

[egdev6]

🔗 Linked Issue

Closes #94

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🏷️ PR Type

• type:bug — Bug fix
• type:feature — New feature
• type:docs — Documentation only
• type:refactor — Code refactoring (no behavior change)
• type:chore — Maintenance, dependencies, tooling
• type:breaking-change — Breaking change

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📝 Summary

• Adds a d keybinding on the TUI sessions list to delete the selected session.
• Requires an explicit y/n/esc confirmation before calling store.DeleteSession.
• Refreshes the session list on success and surfaces store safety errors when deletion is blocked.

📂 Changes

File	Change
internal/tui/model.go	Add session delete state, result message, and store-backed delete command.
internal/tui/update.go	Add sessions-list delete keybinding, confirmation state machine, success refresh, and error handling.
internal/tui/view.go	Render delete confirmation prompt and advertise the delete keybinding.
internal/tui/update_test.go	Cover prompt open/cancel, confirm success, blocked delete errors, and empty-list no-op.
internal/tui/view_test.go	Cover delete confirmation rendering and help options.

🧪 Test Plan

• Unit tests pass locally: go test ./...
• E2E tests pass locally: go test -tags e2e ./internal/server/...
• Manually tested the affected functionality

Additional focused validation:

• go test ./internal/tui/...
• go test ./internal/store -run DeleteSession
• go test -cover ./internal/tui ./internal/store (internal/tui: 99.0%, internal/store: 78.3%)

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🤖 Automated Checks

These run automatically and all must pass before merge:

Check	What it verifies	Status
Check Issue Reference	PR body contains Closes #N / Fixes #N / Resolves #N	⏳
Check Issue Has status:approved	Linked issue has status:approved label	⏳
Check PR Has type:* Label	PR has exactly one type:* label	⏳
Unit Tests	go test ./... passes	⏳
E2E Tests	go test -tags e2e ./internal/server/... passes	⏳

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✅ Contributor Checklist

• I linked an approved issue above (Closes #N)
• I added exactly one type:* label to this PR
• I ran unit tests locally: go test ./...
• I ran e2e tests locally: go test -tags e2e ./internal/server/...
• Docs updated (if behavior changed)
• Commits follow conventional commits format
• No Co-Authored-By trailers in commits

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💬 Notes for Reviewers

This implements only the remaining TUI scope from the latest maintainer comment on #94. Store, HTTP, and CLI session deletion already exist; this PR reuses store.DeleteSession and lets the store enforce safety rules such as blocking sessions with observations.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds an interactive “delete session” flow to the TUI sessions screen, including a confirmation prompt, keybindings, and coverage for the new behavior.

Changes:

• Render a session delete confirmation prompt in the Sessions view and update help text to advertise the delete keybinding.
• Add delete prompt state + delete command/message handling to the TUI update loop.
• Add unit tests for the prompt rendering and delete keyflow (confirm/cancel, success/failure).

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
internal/tui/view.go	Renders delete confirmation prompt and updates Sessions help text to include delete key.
internal/tui/update.go	Handles delete prompt keyflow, processes delete results, and clamps cursor/scroll after sessions refresh.
internal/tui/model.go	Adds delete-related model state, message type, and delete command.
internal/tui/view_test.go	Tests that the delete prompt renders expected content.
internal/tui/update_test.go	Tests delete prompt open/cancel/confirm flows and error handling.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

[egdev6]

Addressed the latest Copilot comments in commit 1ffa160:

• handleSessionsKeys now accepts both d and D for opening the session delete prompt.
• Replaced the two delete-state booleans with a single explicit SessionDeleteState enum (None, Prompt, Deleting) to prevent invalid prompt/deleting combinations.

Validation after the fix:

• go test ./internal/tui/...
• go test ./internal/store -run DeleteSession
• go test ./...
• go test -cover ./internal/tui ./internal/store

PR still needs a maintainer to add exactly one label: type:feature.

[egdev6]

@Alan-TheGentleman ready for review!

[Alan-TheGentleman]

This is the focused #94 slice we want: session deletion in the TUI with confirmation. I added the type:feature label so the process gate can run again. Once checks are green, this is the deletion PR to review before the broader alternatives.