feat(runtime): invoke runtimes and endpoints from TUI details

[aidandaly24]

Description

Adds contextual actions to the Runtime TUI so users can act on an already-selected Runtime or endpoint without selecting it again.

• Adds invoke as the primary action on the Runtime details screen.
• Replaces the Runtime endpoint JSON-only destination with a summary and action screen.
• Adds direct endpoint invocation and preserves complete JSON on a child route.
• Surfaces an endpoint failureReason in the summary when the service provides one.
• Preserves the originating details screen when leaving contextual invoke flows.

Related Issue

Closes #1974

Documentation PR

Not required. This changes interactive navigation without changing CLI syntax or public command documentation.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Additional validation:

• bun test --coverage --coverage-reporter=lcov — 1057 pass, 0 fail
• Focused Runtime screen tests — 63 pass, 0 fail
• Runtime endpoint/detail screen tests — 33 pass, 0 fail
• bun run format:check
• bun run build
• Live read-only Runtime and endpoint flows with AWS_PROFILE=deploy in the TUI harness

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the
terms of your choice.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.81%. Comparing base (1e7de20) to head (3cfa9fe).
⚠️ Report is 13 commits behind head on refactor.

Additional details and impacted files

@@             Coverage Diff              @@
##           refactor    #1975      +/-   ##
============================================
+ Coverage     96.79%   96.81%   +0.01%     
============================================
  Files           306      306              
  Lines         17051    17137      +86     
============================================
+ Hits          16505    16591      +86     
  Misses          546      546              

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[nborges-aws]

Clean; LGTM