Fix inert OSC-8 hyperlinks: bump vendored x/vt to upstream parser fix

[anutron]

Why

OSC-8 terminal hyperlinks (e.g. clickable #960 PR references in Claude Code's status line) are inert everywhere in Argus, including panes that already have the hyperlink-style mapping wired up (UvCellToTcellStyle → tcell.Style.Url).

Root cause: Argus's vendored github.com/charmbracelet/x/vt (pinned to commit f2fb44ab3145) has a parser bug in vt/osc.go's handleHyperlink — for an OSC-8 sequence that includes an id= param (ESC ] 8 ; id=1vaggxp ; https://... ST, the exact form Claude Code emits), the two OSC data segments are assigned to the wrong struct fields: cell.Link.URL receives the id=... params segment and cell.Link.Params receives the real URL. Every downstream consumer faithfully renders a syntactically valid but useless hyperlink whose href is the literal string "id=1vaggxp" — text displays styled (orange/underlined) but Option/Cmd-click does nothing.

Already fixed upstream: github.com/charmbracelet/x/vt commit 3c30eef5e73e8ad8e1765913b0ca2aeb43d32e4f ("fix(vt): store osc 8 hyperlink params and uri in correct fields (#868)", merged 2026-08-28).

What changed

• Bumped github.com/charmbracelet/x/vt to the exact upstream fix commit (pinned rather than @latest, to avoid pulling in two extra days of unrelated upstream changes). github.com/charmbracelet/x/ansi moves 0.11.6 → 0.11.7 as a coordinated transitive requirement (confirmed via go mod tidy — the fix itself lives entirely in x/vt).
• No Argus code changes — the bug lived entirely in the vendored dependency; UvCellToTcellStyle's existing cell.Link.URL → Style.Url(...) mapping was already correct.
• New regression test TestOSC8HyperlinkWithIDParam_RealWireFormat (internal/tui/terminal/terminalpane_test.go) drives the real x/vt emulator with the actual OSC-8 wire-format bytes Claude Code emits, instead of a hand-built uv.Cell — the exact gap that let this ship with zero test coverage. Verified it fails on the old pinned commit with the predicted swapped values, and passes on the fix.
• Gotcha note added to context/knowledge/gotchas/pty-terminal.md.
• OpenSpec change authored and archived within this PR (openspec/specs/terminal-rendering/spec.md gains an "OSC-8 hyperlink rendering" requirement) per this repo's spec-driven-development convention for behavioral fixes.

Out of scope: internal/tui/terminalpane/terminalpane.go (the plugin-view pane) — only exists on an unmerged sibling branch (PR #960); it inherits this fix automatically once merged, since it depends on the same corrected x/vt cell data.

Test plan

• TestOSC8HyperlinkWithIDParam_RealWireFormat passes on the fix, and was confirmed to fail (with the exact predicted swap) against the old pinned x/vt commit
• make pre-pr — build/vet/fmt-check/lint-pr all clean; test-cover-gate clean at 88.7% coverage (two pre-existing, unrelated local-only false-fails excluded: hera-worker env-var leakage into internal/agent profile-env tests, and the advisory-only make vuln stdlib-CVE gate that CI itself runs as continue-on-error)

🤖 Generated with Claude Code

[github-actions]

Merging this branch will not change overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/drn/argus/internal/tui/terminal	96.95% (ø)

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Coverage by file

Changed unit test files

• github.com/drn/argus/internal/tui/terminal/terminalpane_test.go