fix: improve error messages — fix ContextError/ResolutionError misuse

[BYK]

Problem

The ContextError and ResolutionError classes produce structured Try: ... Or: ... error messages, but they're misused in ~15 call sites, producing confusing output. Real Sentry issues confirm this affects hundreds of users:

• CLI-7V (127 events, 35 users): Project is required. Specify it using: No project 'patagonai' found...
• CLI-4A (21 events, 13 users): Project 'AGENT-API' not found is required.
• CLI-EZ: Trace ID and span ID is required. (grammar) + irrelevant DSN alternatives

Changes

Error class fixes:

• Fix grammar: "X and Y is required" → "are required" for compound resources
• Convert 8 ContextError misuses to ResolutionError (org-list, project/list, issue/list, project/create, resolve-team, project/view, resolve-target)
• Convert pagination cursor error to ValidationError
• Pass alternatives: [] at 14 sites where DSN hints are irrelevant (Trace ID, Log ID, Event ID, Span ID)

event view enhancement:

• Issue URLs (/issues/123/) now fetch the latest event via getLatestEvent() instead of throwing a confusing error about missing event IDs

Prevention measures:

• Runtime assertion in ContextError constructor: command must be single-line (throws on \n)
• CI check script (script/check-error-patterns.ts) scanning for multiline ContextError commands and ad-hoc Try: patterns in CliError
• Added check:errors step to CI workflow
• Updated AGENTS.md with error class selection guidance

Fixes CLI-7V, CLI-4A, CLI-EZ, CLI-CC, CLI-DQ

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

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Bug Fixes 🐛

• Improve error messages — fix ContextError/ResolutionError misuse by BYK in #456

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[github-actions]

Codecov Results 📊

✅ 116 passed | Total: 116 | Pass Rate: 100% | Execution Time: 0ms

📊 Comparison with Base Branch

Metric	Change
Total Tests	—
Passed Tests	—
Failed Tests	—
Skipped Tests	—

✨ No test changes detected

All tests are passing successfully.

✅ Patch coverage is 97.80%. Project has 1139 uncovered lines.
✅ Project coverage is 95.2%. Comparing base (base) to head (head).

Files with missing lines (4)

File	Patch %	Lines
resolve-target.ts	82.72%	⚠️ 117 Missing
arg-parsing.ts	94.41%	⚠️ 19 Missing
org-list.ts	95.40%	⚠️ 18 Missing
view.ts	93.97%	⚠️ 12 Missing

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    95.19%    95.20%    +0.01%
==========================================
  Files          175       175         —
  Lines        23699     23729       +30
  Branches         0         0         —
==========================================
+ Hits         22560     22590       +30
- Misses        1139      1139         —
- Partials         0         0         —

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