[feature] status refetch support (#1690)

* revamp http client to not limit requests, instead use sender worker

Signed-off-by: kim <grufwub@gmail.com>

* remove separate sender worker pool, spawn 2*GOMAXPROCS batch senders each time, no need for transport cache sweeping

Signed-off-by: kim <grufwub@gmail.com>

* improve batch senders to keep popping recipients until remote URL found

Signed-off-by: kim <grufwub@gmail.com>

* fix recipient looping issue

Signed-off-by: kim <grufwub@gmail.com>

* move request id ctx key to gtscontext, finish filling out more code comments, add basic support for not logging client IP

Signed-off-by: kim <grufwub@gmail.com>

* first draft of status refetching logic

Signed-off-by: kim <grufwub@gmail.com>

* fix testrig to use new federation alloc func signature

Signed-off-by: kim <grufwub@gmail.com>

* fix log format directive

Signed-off-by: kim <grufwub@gmail.com>

* add status fetched_at migration

Signed-off-by: kim <grufwub@gmail.com>

* remove unused / unchecked for error types

Signed-off-by: kim <grufwub@gmail.com>

* add back the used type...

Signed-off-by: kim <grufwub@gmail.com>

* add separate internal getStatus() function for derefThread() that doesn't recurse

Signed-off-by: kim <grufwub@gmail.com>

* improved mention and media attachment error handling

Signed-off-by: kim <grufwub@gmail.com>

* fix log and error format directives

Signed-off-by: kim <grufwub@gmail.com>

* update account deref to match status deref changes

Signed-off-by: kim <grufwub@gmail.com>

* very small code formatting change to make things clearer

Signed-off-by: kim <grufwub@gmail.com>

* add more code comments

Signed-off-by: kim <grufwub@gmail.com>

* improved code commenting

Signed-off-by: kim <grufwub@gmail.com>

* only check for required further derefs if needed

Signed-off-by: kim <grufwub@gmail.com>

* improved cache invalidation

Signed-off-by: kim <grufwub@gmail.com>

* tweak cache restarting to use a (very small) backoff

Signed-off-by: kim <grufwub@gmail.com>

* small readability changes and fixes

Signed-off-by: kim <grufwub@gmail.com>

* fix account sync issues

Signed-off-by: kim <grufwub@gmail.com>

* fix merge conflicts + update account enrichment to accept already-passed accountable

Signed-off-by: kim <grufwub@gmail.com>

* remove secondary function declaration

Signed-off-by: kim <grufwub@gmail.com>

* normalise dereferencer get status / account behaviour, fix remaining tests

Signed-off-by: kim <grufwub@gmail.com>

* fix remaining rebase conflicts, finish commenting code

Signed-off-by: kim <grufwub@gmail.com>

* appease the linter

Signed-off-by: kim <grufwub@gmail.com>

* add source file header

Signed-off-by: kim <grufwub@gmail.com>

* update to use TIMESTAMPTZ column type instead of just TIMESTAMP

Signed-off-by: kim <grufwub@gmail.com>

* don't pass in 'updated_at' to UpdateEmoji()

Signed-off-by: kim <grufwub@gmail.com>

* use new ap.Resolve{Account,Status}able() functions

Signed-off-by: kim <grufwub@gmail.com>

* remove the somewhat confusing rescoping of the same variable names

Signed-off-by: kim <grufwub@gmail.com>

* update migration file name, improved database delete error returns

Signed-off-by: kim <grufwub@gmail.com>

* formatting

Signed-off-by: kim <grufwub@gmail.com>

* improved multi-delete database functions to minimise DB calls

Signed-off-by: kim <grufwub@gmail.com>

* remove unused type

Signed-off-by: kim <grufwub@gmail.com>

* fix delete statements

Signed-off-by: kim <grufwub@gmail.com>

---------

Signed-off-by: kim <grufwub@gmail.com>

internal/cache/util.go

@@ -74,8 +74,14 @@ func tryStop[ValueType any](cache *result.Cache[ValueType], sweep time.Duration)
 func tryUntil(msg string, count int, do func() bool) {
 	for i := 0; i < count; i++ {
 		if do() {
+			// success.
 			return
 		}
+
+		// Sleep for a little before retry (a bcakoff).
+		time.Sleep(time.Millisecond * 1 << (i + 1))
 	}
+
+	// panic on total failure as this shouldn't happen.
 	log.Panicf(nil, "failed %s after %d tries", msg, count)
 }