XEP-0115 Entity Capabilities: compliance fixes for §5.4 and §6.2

[Copilot]

Openfire's XEP-0115 implementation claimed Version 1.4 compliance but had several gaps against the §5.4 processing method and §6.2 discovery rules.

Fixes

• Missing node attribute in disco#info requests (§6.2 — MUST): Outbound capability queries were sent without the required node attribute on <query>. Per spec, its value must be {caps-node}#{ver} for backwards-compatibility with legacy clients.

  <!-- Before -->
  <query xmlns='http://jabber.org/protocol/disco#info'/>
  
  <!-- After -->
  <query xmlns='http://jabber.org/protocol/disco#info'
         node='http://example.com/client#QgayPKawpkPSDYmwT/WM94uAlu0='/>

• Non-conforming data forms included in ver hash (§5.4 item 6): getExtendedDataForms() included all <x xmlns='jabber:x:data'> forms unconditionally. Forms without a FORM_TYPE field, or where FORM_TYPE is not type='hidden', must be ignored per spec — producing incorrect hashes for affected clients.

• No ill-formed response detection (§5.4 items 3–5): isValid() only checked the hash. Added isWellFormed() (called first) that rejects responses with duplicate identities, duplicate features, multiple forms sharing a FORM_TYPE, or a FORM_TYPE field with conflicting values.

Minor

• Updated class Javadoc version from 1.4 → 1.5 (the last version with substantive implementation changes; 1.6.0 only adds preimage attack documentation).
• Fixed broken @see HTML anchor tags in EntityCapabilitiesManager and EntityCapabilitiesListener.

Tests

Added 6 targeted unit tests covering: ignored form without FORM_TYPE, ignored form with non-hidden FORM_TYPE, and all four ill-formed response rejection cases.

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