examples: add minimal planning + connectors example dirs

[saurabhjain1592]

Context

QF-10 (Phase 1 quality-freeze) added an examples/basic/ minimal smoke
example for the Java SDK and wired it into the new live-stack
integration.yml workflow. The QF epic also calls out planning and
connectors as missing example surfaces for the Java SDK.

What

Add minimal one-class-per-dir examples mirroring the Go SDK layout:

• examples/planning/ — exercises generatePlan + executePlan
• examples/connectors/ — exercises listConnectors (read-only,
  works against community without external credentials)

Each gets a sibling pom.xml like examples/basic/pom.xml so it can be
run via mvn -q compile exec:java.

Why this is a separate issue

Scoping the QF-10 PR tightly: basic is enough to validate the
live-stack integration workflow end-to-end. planning requires an LLM
provider configured against the community stack (often unavailable in
CI), and connectors is straightforward but adds review surface that
isn't on the QF-10 critical path.

Acceptance

• examples/planning/ exists and runs against http://localhost:8080
• examples/connectors/ exists and runs against http://localhost:8080
• Optionally extend the live-integration job in integration.yml to
  include them (only after confirming community-stack LLM availability
  in CI for planning)