fix(setup): unblock clean Linux installs and add enabled_tables allowlist

- Pin managed Python runtime to 3.13 via `uv venv --python 3.13` so installs
  don't pick the system 3.12 on Ubuntu 24.04 and fail at wheel install.
- Sanitize NO_PROXY/no_proxy for the daemon child process — drop IPv6 CIDR
  entries that httpx rejects with InvalidURL (OrbStack injects these by
  default).
- Add `enabled_tables` allowlist on warehouse connections (zod schema +
  live-database introspection filter) to scope ingest to specific tables.
- Add `getting-started/troubleshooting-linux` docs page covering the Python
  3.13 prerequisite, IPv6 proxy gotcha, and a minimal working recipe; link
  it from the quickstart troubleshooting table and the llms-docs map.
- Make docs-site origin overridable via `KTX_DOCS_ORIGIN` so local builds
  can serve under host.docker.internal.

packages/context/src/project/driver-schemas.ts

@@ -27,6 +27,12 @@ function warehouseConnectionSchema<const Driver extends WarehouseDriver>(driver:
         .min(1)
         .optional()
         .describe('Warehouse connection URL or DSN; may contain environment-variable references like env:DATABASE_URL.'),
+      enabled_tables: z
+        .array(z.string().min(1))
+        .optional()
+        .describe(
+          'Optional allowlist of fully-qualified table names ("schema.table") to ingest. When set, live-database ingest discards any table whose schema-qualified name is not in this list. Useful for smoke-testing deep ingest on a single table.',
+        ),
     })
     .describe(
       `${driver} warehouse connection. Additional driver-tunable fields (e.g. historicSql, context.queryHistory) are accepted and passed through.`,