refactor(8.0): remove the 4 deprecated query-operator aliases (clean break)

8.0 keeps the canonical operators (eq/ne/gt/gte/lt/lte) and their clean
long-form aliases (equals/notEquals/greaterThan/greaterThanOrEqual/lessThan/
lessThanOrEqual), and drops the four redundant deprecated spellings:
  is → eq,  isNot → ne,  greaterEqual → gte,  lessEqual → lte

Removed from every evaluator (metadataIndex criteria + range switches,
metadataFilter, the db whereMatcher egress path) and from the
BrainyFieldOperators type, the unsupported-operator error message, the docs
(QUERY_OPERATORS / api README / VFS projection + semantic guides), and the
whereMatcher alias tests. Also migrated Brainy's own internal use — the VFS
TemporalProjection queried with greaterEqual/lessEqual, which would have
silently broken — to gte/lte.

Full gate green: build, unit 1512, integration 607.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/api/README.md

@@ -413,9 +413,9 @@ Brainy uses clean, readable operators (BFO — Brainy Field Operators):
 | `equals` / `eq` | Exact match | `{age: {equals: 25}}` |
 | `notEquals` / `ne` | Not equal | `{status: {notEquals: 'deleted'}}` |
 | `greaterThan` / `gt` | Greater than | `{age: {greaterThan: 18}}` |
-| `greaterEqual` / `gte` | Greater or equal | `{score: {greaterEqual: 90}}` |
+| `gte` / `greaterThanOrEqual` | Greater or equal | `{score: {gte: 90}}` |
 | `lessThan` / `lt` | Less than | `{price: {lessThan: 100}}` |
-| `lessEqual` / `lte` | Less or equal | `{rating: {lessEqual: 3}}` |
+| `lte` / `lessThanOrEqual` | Less or equal | `{rating: {lte: 3}}` |
 | `between` | Inclusive range | `{year: {between: [2020, 2025]}}` |
 | `oneOf` / `in` | In array | `{color: {oneOf: ['red', 'blue']}}` |
 | `noneOf` | Not in array | `{status: {noneOf: ['deleted']}}` |