docs: monitoring-service terminology, verdict permanence, deployments manifest

[mfw78]

• "watch-tower" → "off-chain monitoring service" across docs and NatSpec
• verdict permanence documented: INVALID uniformly terminal, NEEDS_INPUT acquisition semantics, the Restriction overlay; breaking-changes table extended
• canonical deployments/networks.json manifest (chainId → registry address, deploy block, topic0 set) with schema README

Issues

Advances #35. The verdict-permanence rows and the deployments/networks.json schema land here, but three of the issue's asks are not finished:

• the rename leaves docs/architecture.md L12 reading "off-chain monitoring service (historically called a watch-tower)s", L102 still reads Watch-Tower, and README.md is untouched (5 occurrences)
• L145 still says "The swap guard is not consulted by checkOrder", which feat!: separate swap-guard restriction from the generator verdict #38 made false (the guard is applied in the shared _poll), and the L220 PollResult snippet omits restriction; the changelog at L554 still describes swap-guard restriction as an INVALID verdict
• networks.json carries an empty networks object, so no chainId -> address / deployBlock / topic0 entry is actually published

Closes #15 - the issue is superseded by the discovery set as a whole (#36 spec, #37-#41 implementation), not by any single PR in it; this is the last of that set. The delivered design differs from the issue's literal proposal: there is no typeId() or version() getter, descriptorURI() returns string[] on a sidecar rather than string on IConditionalOrderGenerator, and BaseConditionalOrder deliberately does not default them. The supersession is recorded in the design note on #15.

Part of #1.