Wire LSP features: hover, go-to-definition, completions, symbols, outline

[joewiz]

Summary

Wires eXist-db's lsp:* XQuery module into the eXide frontend, adding five LSP-backed features. Depends on the feature/lsp-module branch in eXist-db/exist.

• Hover tooltips — CM6 hoverTooltip extension calls lsp:hover() and renders function signatures and documentation when hovering over XQuery symbols
• Go-to-definition — replaces AST-based lookup with lsp:definition() for accurate jump-to-source including imported modules
• Function completions — replaces the old GET endpoint with lsp:completions() which includes user-defined local functions; prefix-filtered server-side; CM6 snippet templates generated from parameter names
• Navigate → Symbol — lsp:symbols() powers the Quick Picker symbol list (Ctrl+Shift+O)
• Outline panel — populated via lsp:symbols() with atomic assignment to prevent race-condition duplicates; click handler fixed to use editorUtils.gotoLine() with correct row/column; outline now activates correctly when split-pane mode is restored from localStorage

What Changed

• modules/api/query.xqm — four new endpoints: POST /api/query/hover, POST /api/query/definition, POST /api/query/completions, POST /api/query/symbols
• modules/api.json — OpenAPI routes for the four new endpoints
• src/lsp-hover.js (new) — CM6 hoverTooltip extension; fetches hover data, renders signature + description
• resources/css/lsp-hover.css (new) — tooltip styles with dark-mode support
• src/editor.js — registers LspHover.extension() in the CM6 extension list
• tools/bundle-cm6.js — exports hoverTooltip from the CM6 bundle
• scripts/bundle.js — includes lsp-hover.js in the esbuild entry
• index.html.tmpl — loads lsp-hover.css
• src/xquery-helper.js — gotoDefinition uses lsp:definition(); gotoSymbol uses lsp:symbols(); createOutline uses lsp:symbols() with regex fallback on failure
• src/xquery-completion.js — fetchFunctionCompletions calls POST /api/query/completions
• src/outline.js — click handler uses editorUtils.gotoLine() with LSP row/column; removed redundant doc.functions = [] reset
• src/preferences.js — activates outline in applyPreferences() when split-pane is restored from localStorage

Prerequisites

eXist-db must have the feature/lsp-module branch deployed, which provides lsp:hover, lsp:definition, lsp:completions, lsp:symbols, and lsp:diagnostics.

Test Plan

• Hover over a function name → tooltip shows signature and documentation
• Go to Definition on a local function → cursor jumps to declaration
• Ctrl+Space mid-function-name → completions include built-ins and user-defined local functions
• Navigate → Symbol (Ctrl+Shift+O) → all declared functions and variables listed
• Outline panel (tabbed mode) → functions appear after clicking the outline tab
• Outline panel (split-pane mode) → functions appear on startup without clicking the tab
• Clicking an outline item → cursor jumps to correct line and column
• No duplicate entries in outline after document save/validate
• All features degrade gracefully when LSP module is not available

🤖 Generated with Claude Code

[joewiz]

Note on CI failures: This PR requires the lsp:* XQuery module from eXist-db core, added in eXist-db/exist#6130. CI will fail until that PR is merged into develop and a build including it is available. The LSP features have been manually verified end-to-end against a local eXist-db instance with the module deployed.