v0.5.0 — runs engine 0.4.3

The plugin now runs validation engine 0.4.3 (it was stuck on 0.3.0), so an agent
sees what the VS Code extension shows:

• Invalid casts are errors: int x = input.float(1.0) no longer passes.
• Misspelled constants are errors: color.purplee, shape.trianglup,
  plot.style_circlez.
• S10, a new info hint: a hard-coded external feed without
  ignore_invalid_symbol halts the script for viewers whose plan cannot read it.
• Wrapped statements are joined before checking, and many false positives
  are gone.
• The edit hook blocks on real errors again. With a local extension checkout
  it had silently found nothing since the extension's engine moved.

MINOR, not PATCH: scripts that validated clean on 0.4.x of this plugin can now
report errors.

The plugin now runs engine 0.4.3, not 0.3.0

package.json pinned pinescript-v6-validator at ^0.3.0. For a 0.x version that
range admits only 0.3.x, so the MCP tool, the hook and the example gate ran engine
0.3.0 and missed every 0.4.x fix while the VS Code extension shipped them. The pin
is now ^0.4.3 (lockfile resolves 0.4.3). What that brings, checked against the
installed package:

• S10 (info hint): a hard-coded external feed in request.*() without
  ignore_invalid_symbol. Checks now ship as S1-S3 and S5-S10; S4 is still
  specified and not built.
• Invalid-cast rule: int x = input.float(1.0) is an error.
• Constant-namespace members are checked: color.purplee, shape.trianglup,
  plot.style_circlez, barstate.islastt are errors. Variables in open
  namespaces (syminfo.*, timeframe.*, chart.*) are still not checked.
• Wrapped statements are joined before validation, and many false-positive fixes.
• The function reference grows from 457 to 475 entries.

tests/engine-version.test.js pins this down: the invalid-cast and
misspelled-constant probes fail on 0.3.0 and pass on 0.4.3, each with a paired
"still clean" case.

Local-checkout fallback finds the current engine layout

The extension's single-engine change removed dist/src/parser/* and dist/v6/*,
so the fallback in the MCP server, the hook and the example gate could no longer
find a checkout. All three now share one resolver, mcp/engine.js, which tries
dist/engine/index.js, then packages/validator/dist/index.js, and returns the
same shape as the npm branch (including validatePineScript).
PINESCRIPT_VALIDATOR, when set, now wins over the npm package — an override that
npm silently beat would test the wrong engine. scripts/validate_pine.js is the
headless CLI the hook and make examples call.

Changed

• One plugin version, 0.5.0, in every file that states it. PLUGIN.md,
  plugin.yaml, the MCP server handshake and all skill metadata said 0.4.2 while
  package.json and the manifests said 0.4.3. tests/version-consistency.test.js
  now fails the gate on any drift, and on a missing CHANGELOG heading.
• scripts/validate_pine.js refuses an empty file list (exit 2) rather than
  exiting 0, and the hook feeds back diagnostics only — resolver notices on
  stderr no longer leak into the message.
• Any engine that loads without validatePineScript is skipped, npm or checkout,
  so a partial engine cannot report a file clean.
• The indicator skill documents S10 with a validated ignore_invalid_symbol
  example; the validation skill no longer calls every non-error finding a warning.
• make examples validates against the plugin's own engine instead of requiring
  an extension checkout, so the gate no longer fails on machines without one.
• README, SPEC, the validation skill and the manifests' "457-function" figure
  updated to the 0.4.3 facts above.