Track confirmed query-qualified Observe relations

[Jason-Morcos]

Stack order: #67 → #68 → #69. This is 2 of 3 and should merge after #67. Until #67 lands, the Files view also includes that prerequisite; the isolated second-layer diff is d33f896...9d38bcc.

Samsung resource trees can expose query-qualified forms of the same href, and their Observe behavior is not uniform. Some responses carry a standards-compliant Observe option, while the appliance behavior documented in #16 can begin with an optionless registration response and later send optionless notifications on the same token.

This change makes the relation state explicit:

• Relation identity is (href, query), so refetch and deregistration preserve the exact registration target.
• A valid Observe option confirms the standards path and its 24-bit sequence is ordered with the RFC 7641 half-range and 128-second reset rules.
• An optionless initial response remains probationary. It is promoted to the legacy path only after a later response arrives with a different Message ID on the same token.
• Pending, confirmed, legacy, and error callbacks are separate, allowing downstream code to distinguish registration progress from a usable relation.
• Malformed Observe options, error responses, token exhaustion, and failed registration sends clean up their partial state rather than leaving a ghost relation.

This layer deliberately does not add the targeted refresh or unsubscribe API and does not change close-time deregistration pacing; those are in the final stack layer.

Validation at 9d38bccc54c8e483828bcdd9feddea5cd08c8618:

• 71 focused lifecycle and Observe relation tests
• 552 full SmartThings-Local tests on both the project interpreter and Python 3.11
• 1,730 LocalThings tests with this head loaded
• clean wheel and sdist builds with verified distribution contents

[QuiteYellow]

Merging this, with one follow-up.

The probationary 2.05's payload does not reach on_notification:

optionless initial 2.05 -> on_notification
  main   [('/a/b', b'INITIAL-STATE')]
  #68    []

Only on_observe_pending fires. On a device that sends no second packet, which
is how you described the laundry machines in #16, the relation stays
probationary and that first response is the only payload it ever produces. Poll
tiers cover the gap, so this is a follow-up.

Is dropping it intended? Delivering the payload while holding the relation
probationary would cover both.

[Jason-Morcos]

It wasn't intended to discard the only representation. #71 delivers the complete initial payload through on_notification while leaving the relation probationary. A same-MID retransmission is still suppressed, and only a later different-MID packet promotes it to the legacy path. If the initial response is blockwise, it goes through the existing full refetch before delivery.

Thanks for catching this distinction.