refactor: Added unpaginated list methods to the Organizations plugin.

[m-t-a97]

List methods returned a page, not a collection, so fetching every member of an organization meant looping until pagination.has_more went false — N round-trips and N SELECT COUNT(*) queries for data one unbounded query returns. The plugin API had no way to ask for a whole collection at all.

Every list method now comes as a pair, and the names say which is which:

• ListAll… takes pagination.Params and returns the List…Response envelope. These are the existing methods, renamed.
• GetAll… takes no pagination and returns a plain slice. These are new, and reuse the names the paginated methods used to occupy.

Because GetAll… keeps its old name against a new signature, every call site that was not updated is a compile error rather than a silent behaviour change.

The pairs exist at the repository, service and plugin API layers. HTTP routes, query parameters and response bodies are unchanged; handlers, their structs and the usecase layer are renamed only.

• Organizations get both an actor-scoped GetAllOrganizations and an unfiltered GetAllOrganizationsUnscoped, backed by new OrganizationRepository.GetAll.
• Invitations get pairs for both collections they expose: by organization, and pending by email.
• Unconstrained queries reuse the same predicates, joins, row mappers and ORDER BY as their paginated twins, so both return rows in the same order. The raw-SQL joins also skip the SELECT COUNT(*), making them a single round-trip where the paginated path takes two, and closing the torn-read window between the count and the page.

GetAllPendingByEmail drops the MaxPendingInvitationsPerBatch = 500 cap, which fixes a bug in AcceptPendingOrganizationInvitationsForEmail. On saturation it logged "remaining invitations will be accepted on the next call" and returned, but nothing re-invokes it, so a user with more than 500 pending invitations silently never had the rest accepted. Note that acceptOrganizationInvitations still processes the batch in a single transaction, which is now unbounded.

Corrects the five list endpoint descriptions in the OpenAPI spec, which have documented a "hard maximum of 100" on limit since 8f08c48 removed MaxLimit, and regenerates openapi.json.

Tests cover ordering, parent scoping, empty-slice-not-nil, relation hydration, repository error propagation and each authorization failure path, plus SQL-backed cases proving the unconstrained methods ignore pagination.DefaultLimit and that more than 500 pending invitations are all accepted.

Known gap, pre-existing and unchanged: api.go bypasses the usecase layer where authorizeOrgAccess lives. The member, team and team-member services authorize themselves, but GetAllInvitations checks only for a non-empty organization ID, so a caller holding *API can read invitations for any organization. This change makes that cheaper to reach rather than newly possible. GetAllOrganizationsUnscoped is documented as administrative-only but is not enforced.

BREAKING CHANGE: the Organizations plugin's exported Go API is renamed. On *API, the service interfaces and the repository interfaces, paginated GetAll… methods are now ListAll…, and the GetAll… names now belong to unpaginated methods returning a plain slice. Embedders calling these must rename their call sites; a call left unchanged will fail to compile rather than silently return a single page.